Field of the Invention
This invention relates to surgical devices for the repair and reconstruction of soft tissue injuries. In particular, this invention relates to devices and methods for the surgical implantation of replacement (autograft or allograft or artificial) ligament grafts. Still more particularly, the invention relates to the surgical repair of anterior cruciate ligament grafts.
Description of the Prior Art
The repair and reconstruction of torn or damaged soft tissues is a common surgical procedure. For example, replacement graft ligaments may be secured at the site of the original ligament. The procedure generally involves drilling bone tunnels into adjacent bones at the site of the original ligament and securing a graft ligament within these bone tunnels. In many applications, such as in the knee joint, such procedures may be performed arthroscopically. The graft ligament may be an autograft, an allograft, a xenograft, or it may be totally artificial and synthetic. Common types of anterior cruciate ligament (ACL) grafts, for example, include ones which may be autologous or allograft bone-patellar tendon-bone or soft tissue (such as semitendinosus and gracilis tendons), both types harvested by techniques well known to those skilled in the art.
The graft ligaments may be secured within the bone tunnels in a variety of ways. Of prime importance is the degree to which they can withstand pullout forces prior to complete healing. For example, it is known to use interference screws inserted parallel to the tunnel axis to compress the ends of the graft ligament against the wall of the bone tunnel to secure the graft ligament and promote tissue in-growth.
Suspensory graft fixation devices have been developed to secure a graft ligament in a bone tunnel. One such device is described in U.S. Pat. No. 8,852,250 (Lombardo et al.), entitled Graft Fixation Implant, assigned to the assignee hereof and incorporated by reference herein. Suspensory graft fixation devices work by lying transversely across the opening of a bone tunnel and generally take the form of an elongated anchor member which suspends a graft retaining loop from a fixation point on the surface of a bone to which the graft is to be attached (in this case, a femur). The elongated member has an axis and a pair of suture receiving apertures symmetrically situated on the axis on opposite sides of the center of the elongated member. In ACL procedures the elongated member, often called a button, is adapted to be situated transversely across the exit opening of the bone tunnel on the lateral femoral cortex so that a supporting loop, generally made of suture material, can be suspended from the button and can extend into the bone tunnel from the suture receiving apertures of the button. The suture loop supports one end of a graft ligament passed through the loop. The term “suture” as used herein may be any type of filamentous material such as a biocompatible or bioabsorbable filament, ribbon, tape, woven or non-woven material capable of providing the loop support and the frictional resistance required by the device described herein. In an arthroscopic procedures such as an ACL reconstruction the elongated anchor member is initially aligned with the axis of the bone tunnel, and pulled through the tunnel to the exit at the distal end on the lateral femur. For such suspensory graft fixation devices to be able to support a graft ligament and to be properly transversely situated at the exit of the bone tunnel, the suture loop and the bone tunnel must both be long enough to enable the elongated member to “flip” from an axially aligned orientation to a transverse orientation when it exits the bone tunnel.
Since the supporting loop of such a suspensory device is most often of a fixed length, graft fixation requires preparation of a graft ligament of predetermined length. Furthermore, because prior art suspensory graft fixation devices have fixed loop lengths they are produced in multiple sizes (ranging, for example, from loop lengths of 15 mm to 60 mm in 5 mm increments in the case of XO Button® implants made by ConMed Corporation, Largo, Fla.) in order to accommodate various graft and tunnel lengths that may be encountered during a surgical procedure. The fixed graft length and variations in tunnel and loop lengths make prior art suspensory ligament fixation challenging.
Recently, suspensory devices have been made with adjustable loop lengths. See, for example, U.S. patent application 2010/0256677, (Albertorio et al.) published Oct. 7, 2010 and entitled Integrated Adjustable Button-Suture-Graft Construct with Two Fixation Devices. It has been found that the adjustability of the loop length of a suspensory graft fixation device may be achieved in a manner considerably less complex than that described in the aforementioned publication.
At times surgeons may encounter situations where they cannot produce a bone tunnel of adequate length to receive a ligament graft suitable for suspensory fixation. A predetermined length of graft ligament is required to engage a predetermined portion of the bone tunnel for proper healing. For example, a so-called short tunnel ACL reconstruction may present a relatively small (narrow) femur which does not enable formation of an adequately long bone tunnel which means, in turn, the suspensory anchor member cannot be advanced far enough out of the tunnel to flip yet keep enough contact between the graft and the bone tunnel wall. Use of an adjustable loop in such situations could nevertheless enable the surgeon to proceed with a suspensory-type repair. Accordingly it is an object of this invention to produce a suspensory graft ligament repair system suitable for short tunnel repairs.
In instances in which soft tissue is to be pulled into a bone tunnel, such as ACL reconstruction, it is desired to have an adjustable loop to simplify the procedure and maximize the bone to soft tissue interface.
It is an object of this invention to produce a suspensory graft fixation device adapted to lock the size and position of the graft supporting loop after it has been set at a desired length.
It is also an object of this invention to automatically lock the graft supporting loop by pulling it in one direction relative to the anchor member, and to vary the length of the graft supporting loop, to resize it, by pulling it in the opposite direction.